What should I do when I know he's lying?

Long and complicated, but please read, I need some advice. I live in NC and he lives in AZ we are both unmarried and in our 30's. We went to high school together in TX and haven't seen each other in over 13 years. He contacted me a couple of months ago, and we started talking again. I have made plans to go and see him in July. I already have a plane ticket (that is non-refundable by the way), hotel reservations and car rental confirmed. In April he all of the sudden said that he needed to cool things down for a while because one of his daughters (she's 10) doesn't want him dating anyone. Ok, so lets take it slow then. He said we would still talk and that he would still call/text me and so far he has barely kept in contact with me. I had made plans to transfer my job, and uproot my kids for this guy. But through some snooping of my own I have found out that he is talking to at least three other women and that he just spent the week with one of them. This other women lives in UT and they went to high school together in Vegas before he meet me in high school. According to her, she has just gone home for the weekend but she is planning on staying with him for the whole summer until at least August. What am I supposed to do now? My heart is broken. I would love to go and see the SW area, but I thought I would be going there to see him and would be moving there by Labor Day. I don't want to just waste the money I have already put out for this vacation but not sure what will happen when I get there. I have tried twice earlier this week to text him and even asked him if there was another women there and of course he said no, but he did said he didn't know if he could see me in July because of his kids. What am I supposed to do now?